One year ago this week, a disturbed young man murdered his mother, then used an assault rifle to kill 20 children and six adults at the Sandy Hook Elementary School in Newtown, Conn. As police converged on him, Adam Lanza killed himself with a Glock handgun.

Guns have been the subject of much politicking since that day but little change in policy. At the federal level, the Senate could not muster the votes to pass enhanced background checks; only a handful of states -- most of them solid blue -- passed gun control measures.

While there has been little action, that does not mean there has been little activity. The Sunlight Foundation is marking this grim anniversary by using our data resources to take a look at how the battle between gun rights and gun control groups has been waged across the country in the year since Sandy Hook. Over the next three days, we'll be presenting our findings in detail. One overall conclusion, however, is hard to avoid: Sandy Hook has meant more money for lobbyists and campaign consultants.

Exactly how many millions have been spent impossible to precisely say as Nancy Watzman details in a pair of stories today. That's because loopholes in disclosure laws mean much of the money isn't publicly reported.

But where we do have disclosure, we can say that gun control interest groups have increased their spending significantly. They upped expenditures on K Street lobbyists -- including former government officials -- to $1.6 million, a fivefold increase over the previous year, as Watzman shows today. Thanks in part to outgoing New York Mayor Michael Bloomberg, gun control groups could match or outspend gun rights forces in 2013 electoral contests, and are heading into 2014 with formidable campaign war chests.

Even so, the National Rifle Association remains a perennial powerhouse in terms of lobbying expenditures and campaign activity. They combined with other gun rights groups to spend at least $6.2 million on lobbying, four times as much as their opponents.

Perhaps that explains why there has been so little legislation passed. Congress has so far sent no new gun control measures to the president's desk; indeed, lawmakers barely made a deadline to extend a ban on guns made of materials that aren't flagged by metal detectors, and refused to ban the manufacture of undetectable weapons using high tech 3-D printers. You can read the Senate debate here. And while some states did pass sweeping new regulations on gun purchases in the wake of Sandy Hook, most of those had a history of stricter gun control laws and safe Democratic legislative majorities. In Colorado, the one swing state where gun control measures have been enacted, the fallout led to two of their supporters being recalled, and a third choosing to resign rather than face voters.

Perhaps the most telling sign that the effort to win new gun control has flagged: The nullification efforts pushed by gun rights groups appear to be stalling out too. Sunlight previously reported on the efforts underway in 40 states to pass laws that would nullify federal legislation calling for bans on certain types of weapons or stiffer background checks. Undertaking the constitutionally questionable effort to override new federal laws makes little sense when new federal laws are unlikely.

In the year since Sandy Hook, its impact on Congress and state lawmakers has diminished. For example, efforts to rein in violent video games and improve mental health services -- the two alternatives that National Rifle Association leaders proposed in the wake of the shooting -- appear to have gotten even less traction. And although the murders that day put a damper on their use for a while, guns remain a popular draw on the campaign cash fundraising circuit, according to a search of our Political Party Time database.